Electronic device

ABSTRACT

An electronic device includes: a casing; a detachable cover having a plate shape forming a part of a top surface of the casing; and an electrostatic touch sensor disposed on an inner surface of the cover to detect a touch location of a finger on an outer surface of the cover.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of theprior Japanese Patent Application No. 2008-152201, filed on Jun. 10,2008, the entire contents of which are incorporated herein by reference.

FIELD

The embodiment discussed herein is related to an electronic devicehaving an electrostatic touch sensor which detects a location touched bya finger.

BACKGROUND

For recent years, as personal computers (hereinafter, referred to asPCs) are widely used, a notebook computer (hereinafter, also referred toas a note PC) as a sort of PCs is being popularized taking advantage ofits portability.

Basically, the notebook computer includes a main unit having a keyboardset on its top surface and an operational circuit such as a CPU inside,and a display unit which has a display screen and is pivoted against themain unit to be freely opened and closed. Although the notebook computeris adapted to use a general mouse to designate a cursor location on adisplay screen, a pointing device is typically integrated to allowoperation to be performed without connecting a general mouse. Althoughthere are many types of integrated pointing devices, a pointing devicehaving an electrostatic touch sensor to move a cursor on the displayscreen by changing a location of a finger on a plane is widely used.

During the initial era of the personal computer, functionality wasconsidered as an important factor, though many PCs have been designed tohave a simple color. For recent years, consumers are interested infashionability as well as portability of the notebook computers, and newtypes having rich color variations are available in the market.

In this regard, an electrostatic touch sensor type pointing device isoften adapted to provide only a touch surface on a top surface of a mainunit. Together with this construction, considering a color variation ofthat area, a number of alternative modules having a different color orshape may be prepared, and then, a module having a desired color orshape may be selectively installed during an assembling process. Forexample, according to a vehicle order system, a desired color isselected by a customer, and then, reflected during the manufacturingprocess. However, typical notebook computers are previously manufacturedwithout reflecting a particular customer's order based on manufacturer'sexpectation. Therefore, in some cases, popular models having aparticular color or shape may be sold out soon after the launching,while unpopular models may remain in a depot for a long time. Moreover,it is very difficult to modify the color or shape of the purchasednotebook computer.

Japanese Laid-open Patent Publication No. 11-15587 discloses a doublefunction unit, having a pointing device on one surface and a number-keyset on the other surface, which is freely connected/disconnected to/fromthe notebook computer. Either surface having a different function can beselectively used as the pointing device or the number-key set byremoving the unit and then reversely installing it.

By modifying this technique such that a general pointing device unit canbe freely installed or removed, it, the color or shape may be selectedor exchanged during or after purchase. However, acquiring additionalexpensive units having a variety of colors and shapes may increase cost,and a user who wants to exchange the unit after purchase mayadditionally buy expensive units.

For recent years, the electrostatic touch sensor has been improved toallow a touch position of a finger to be detected with a sufficientsensitivity even when a plate is additionally overlaid.

Accordingly, the electronic device disclosed in this document isconstructed to allow only a planar cover to be freely removed andinstalled. Since only the cover is exchanged, a variety of colors orshapes can be prepared without significantly increasing cost.Manufacturers may present a number of covers to customers withoutsignificantly increasing cost to allow them to freely enjoy colorvariations.

SUMMARY

An electronic device includes:

a casing;

a detachable cover having a plate shape forming a part of a top surfaceof the casing; and

an electrostatic touch sensor disposed on an inner surface of the coverto detect a touch location of a finger on an outer surface of the cover.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating appearance of a notebookcomputer (or a laptop computer) as an electronic device in an openposition according to an embodiment of the present invention;

FIG. 2 is a perspective view illustrating appearance of a notebookcomputer (or a laptop computer) in a closed position according to theembodiment of the present invention;

FIG. 3 is an exploded perspective view illustrating the notebookcomputer of FIG. 1 and FIG. 2 by removing a cover of a touch sensor froma main unit;

FIG. 4 is a perspective view illustrating a backside of the cover;

FIG. 5 is a partially exploded perspective view illustrating appearanceof the notebook computer when the cover is removed and further a sensorboard is removed;

FIG. 6 is a perspective view illustrating backsides of the sensor boardand the cover;

FIG. 7 is a perspective view illustrating a conventional pointingdevice;

FIG. 8 is a perspective view illustrating a rear side of the notebookcomputer illustrated in FIG. 1 and FIG. 2 in the closed position;

FIG. 9 is a perspective view illustrating a rear side of the notebookcomputer by removing cover members;

FIG. 10 is a partially exploded perspective view illustrating thenotebook computer and a cover member which covers an area of a topsurface of the main unit, which area is closer to the hinge section, ina state in which the cover member is removed;

FIG. 11 is a partially enlarged perspective view illustrating componentsinside a circle R1 of FIG. 10;

FIG. 12 is a partially enlarged perspective view illustrating componentsinside a circle R2 of FIG. 10;

FIG. 13 is a perspective view illustrating the cover member which coversa rear side of a notch portion of FIG. 8;

FIG. 14 is a top plan view illustrating a part of a hinge section of thenotebook computer in the closed position;

FIG. 15 is a perspective view illustrating appearance of a notebookcomputer in an open position according to a comparative example;

FIG. 16 is a perspective view illustrating a cover member of a notebookcomputer according to a comparative example;

FIG. 17 is a perspective view illustrating a rear side of a notebookcomputer in a closed position according to the comparative example;

FIG. 18 is an enlarged view illustrating a notch portion formed bymaking a cut in a hinge cover section;

FIG. 19 is a top plan view illustrating a part of the hinge section ofthe notebook computer in the closed position according to thecomparative example;

FIG. 20 is a perspective view illustrating a backside of the notebookcomputer of FIG. 1 and FIG. 2 according to the embodiment of the presentinvention with a bottom cover being removed;

FIG. 21 is a perspective view illustrating a circuit board unit removedfrom the main unit of FIG. 20;

FIG. 22 is a perspective view illustrating a backside of the circuitboard unit of FIG. 21;

FIG. 23 is a partially enlarged perspective view illustrating componentsinside a circle R3 of FIG. 22;

FIG. 24 is a partially enlarged perspective view illustrating componentsinside the circle R3 of FIG. 22 as viewed from an angle different fromthat of FIG. 23;

FIG. 25 is a partially enlarged perspective view illustrating componentsinside the circle R3 of FIG. 22 with the power connector beingdisconnected by removing the support member;

FIG. 26 is a perspective view illustrating a supporting member;

FIG. 27 is a schematic diagram illustrating a counterpart connector tobe mated with the power connector on the circuit board;

FIG. 28 is a perspective view illustrating a heat sink unit on thecircuit board by removing fixing screws used for fixing to the circuitboard and the support member;

FIG. 29 is a perspective view illustrating a backside, which faces thecircuit board, of the heat sink unit removed from the circuit board;

FIG. 30 is an exploded perspective view illustrating the heat sink unitby removing a cooling fan and separating a cooling member from anattachment member; and

FIG. 31 is a perspective view illustrating the attachment member byremoving a coil spring.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described.

FIGS. 1 and 2 are perspective views illustrating appearance of anotebook computer (or a laptop computer) as an electronic device in anopen position and a closed position according to an embodiment of thepresent invention. The notebook computer 10 includes a main unit 20 anda display unit 30. The display unit 30 is connected to the main unit 20by a hinge so as to be freely opened and closed.

The main unit 30 includes a keyboard set 21, a pointing device 22, apower button 23, and a variety of function buttons 24 on a top surface,and a power connector 25 connected to an AC adaptor and other connectorson side surfaces.

The display unit 30 is provided with a display screen 31 arranged on asurface facing the main unit 20 in a closed position of FIG. 2, and alocking mechanism 32 arranged in an upper center in an open position ofFIG. 1 to prevent the display unit 30 from being erroneously opened froma closed position of FIG. 2. The pointing device 22 includes anelectrostatic touch sensor 22 a for detecting a touch position of afinger and left and right buttons 22 b and 22 c. The touch sensor 22 adetects a movement locus of a finger and reflects the locus on themovement of the cursor on the display screen 31 when a user's fingertouches the sensor 22 aand makes movement. The touch sensor 22 acorresponds to a mouse most widely used as a pointing device. Also, theleft and right buttons 22 b and 22 c of the touch sensor 22 a correspondto the left and right buttons of the mouse.

A fingerprint sensor 26 may be provided in the center between the leftand right buttons 22 b and 22 c to remove necessity of inputtingpasswords or the like.

(Pointing Device)

FIG. 3 is an exploded perspective view illustrating the same notebookcomputer as that of FIGS. 1 or 2 with the cover of the touch sensor 22 abeing removed from the main unit. FIG. 4 is a perspective viewillustrating a backside of the cover 221. FIG. 5 is a perspective viewillustrating a notebook computer with the cover 221 and the sensor board222 being removed. FIG. 6 is a perspective view illustrating backsidesof the cover 221 and the sensor board 222.

The sensor board 222 has a sensor circuit 222 a mounted on its backsideas illustrated in FIG. 6. On the other hand, as illustrated in FIG. 5,the main unit 20 has an opening 223 opened toward both the inside andoutside of the main unit 20 in a location where the sensor board 22 isto be disposed. The sensor board 222 is arranged to allow the sensorcircuit 222 a to be inserted into the opening 223. Edges of the sensorcircuit 222 a are adhered to edges of the opening 223 with adouble-coated fixing tape. In addition, a cable (not illustrated in thedrawing) is extended from the sensor circuit 222 a and connected to theinternal circuit through the opening 223. Although this sensor board 222is adapted to detect a location of a finger touching its surface or amovement locus of a finger when the finger moves on its surface, thesensor board 222 may be adapted to detect a location of a finger just byclosely approaching a finger to the surface without perfectly touching.

Therefore, in this case, the cover 221 is mounted on the sensor board222, and the location of a finger is detected by disposing a finger onthe cover 221. Two engagement claws 221 a are formed on each of the leftand right edges of the cover 221. The main unit 20 also has engagementholes 224, into which the engagement claws 221 a are inserted into, onthe left and right sides of a portion where the cover 221 is disposed.The engagement claws 221 a of the cover 221 are engaged with theengagement holes 224 of the main unit 20 to allow the cover 221 to forma part of a top surface of a main unit casing. If preferably, the cover221 may be adapted to be removed without using any tool. As a result, itis possible to provide a notebook computer of rich color design bypreparing a variety of colors and shapes of the cover 221.

FIG. 7 is a diagram illustrating a conventional pointing device 922.

The pointing device 922 illustrated in FIG. 7 as a comparative exampleincludes an electrostatic touch sensor 922 a, left and right buttons 922b and 922 c, and a fingerprint sensor 926 disposed between the buttons922 b and 922 c. Since the touch sensor 922 a is disposed inside theopening 923 formed on the main unit casing, it is difficult to removeit. In addition, the touch sensor 922 a is quite deeply disposed to anextent equal to the thickness of the main unit casing.

(Hinge Section Structure)

FIG. 8 is a perspective view illustrating a rear side of the notebookcomputer of FIGS. 1 or 2 in a closed position.

The notebook computer 10 has an air outlet 27 and other variousconnectors and components on a rear side of the main unit 20. Now, astructure of the hinge section 40 connecting the main unit 20 and thedisplay unit 30 to each other will be described. The hinge section 40 isshaped like a single cylinder extending in a predetermined directionthat is a longitudinal direction of the notebook computer 10 in thiscase. Looking at the cylindrical hinge section, a cylindrical rodsection 41 is covered by remaining portions other than a pair of covermembers 43 longitudinally separated and is inserted into a part of thedisplay unit 30 casing (i.e., a bottom portion of the display unit 30when the display unit 30 is open relative to the main unit 20, i.e., inan open position as illustrated in FIG. 1). Notch portions 42 (see FIG.9) each formed by making a cut in the cylindrical shape are covered by apair of cover members 43. Fastening elements for the cover members 43are screws, and heads of the screws are covered by patches 43 a.

FIG. 9 is a perspective view illustrating a rear side of a notebookcomputer with the cover member being removed.

Referring to FIG. 9, inside of the portion covered by the cover member43 (see FIG. 8) is revealed, where the notch portion 42 appears. Thenotch portion 42 is included in a part of the display unit 30 casing andformed by making a cut in the rod section 40 in the left and rightportions. In the notch portion 42, there can be seen a part of themovable section 452 of the hinge unit 45 (see FIGS. 11 and 12), and ascrew hole 273 to which a screw is fastened to install the cover member43 (see FIG. 8).

FIG. 10 is a partially exploded perspective view illustrating thenotebook computer 10 and a cover member 27 that covers an area closer tothe hinge section 40 of a top surface of the main unit, in a state inwhich the cover member 27 is removed from the notebook computer 10.

The area of the top surface of the main unit 20, which area is closer tothe hinge section 40 of the notebook computer, is covered by a covermember 27. This cover member 27 includes a plate portion 271 forming apart of the top surface of the main unit 20 and a pair of risingportions 272 erected in an arc shape from ends of the plating section271. On the back side (not illustrated) of the plate portion 271, aswitch board having switches for detecting pressing of the power button23 or a variety of function buttons 24 are fixed.

The pair of the rising portions 272 of the cover member 27 have an arcshape fitted to the cylindrical contour of the rod section 41 includedin a part of the display unit 30 casing and covers a front side of thenotch portion 42 (also, referred to as a first space). A fastener havinga screw hole 273 of FIG. 9 is erected on a backside of the risingportion 272.

FIGS. 11 and 12 are enlarged perspective views illustrating componentsinside circles R1 and R2 of FIG. 10.

FIG. 11 illustrates a right-side notch portion of FIG. 10, and FIG. 12illustrates a left-side notch portion of FIG. 10.

The notch portion 42 of FIGS. 11 and 12 includes a hinge member 45 thatrotatably supports the display unit 30 against the main unit 20. Thehinge member 45 has a fixed section 451 and a movable section 452. Thefixed section 451 is fastened to an end of the main unit 20 by screws.The movable section 452 has a shaft 452 a fixed to the fixed section 451and a rotatable section 452 b which rotates while causing frictionagainst the axel 452 a. Also, the rotatable section 452 b is fixed tothe display unit 30. Since the hinge members 45 each having such astructure are provided at both sides, the display unit 30 can be openedto a larger extent relative to the main unit 20 than that illustrated inFIG. 1 from the closed position of FIG. 2, and can also be returned tothe closed position.

A wall of the display unit 30 casing forming the notch portion 42 hasribs 46 arranged side by side and vertically erected. Each of the ribs46 has an arc shape fitted to the cylindrical contour of the rod section41. Effects of the arc shape will be described later.

FIG. 13 is a perspective view illustrating a cover member which covers arear side of a notch portion of FIG. 8.

The cover member 43 has an arc shape fitted to the cylindrical contourof the rod section 41 (see FIGS. 8 to 12). As illustrated in FIG. 8, thecover member 43 covers the rear side corresponding to a second space ofthe notch portion 42. The left and right cover members 43 have the sameshape for the left and right notch portions 42. The cover member 43 hasa central attachment hole 431. The attachment hole 431 is communicatedby a screw to the screw hole 273 (see FIG. 9) formed in a rear side ofthe rising portion 272 of another cover member 27 of FIG. 10. The headof the screw is covered by a patch 43 a (see FIG. 8). As a result, thecover member 43 and the rising portion 272 of the counterpart covermember 27 of FIG. 10 are combined with each other to form a cylindricalcontour directly extended from the rod section 41. Depending on the rodsection 41, the hinge section 40 has harmonious design by having theshape of a single cylinder extending from the left end to the right endof the notebook computer.

FIG. 14 is a top plan view illustrating a part of the hinge section ofthe notebook computer in the closed position.

The notch portion 42 is covered by the cover member 43 of FIGS. 8 and 13and the rising portion 272 of the counterpart cover member 27 of FIG. 10(see FIGS. 9 to 12), so as to harmoniously form a cylindrical shape incombination with the cylindrical rod section 41. In this case, asillustrated in FIGS. 11 and 12, the ribs 46 are arranged side by side inthe notch portion 42 and each have an arc shape fitted to thecylindrical contour of the rod section 41. Therefore, even when thedisplay unit 30 is closed on top of the main unit 20, a part of thedisplay unit 30 casing is overlapped with a part of the rising portion272 on a top plan view, so that it can also provide harmonious designwith no gap. In this regard, the comparative example described belowwill facilitate understanding of this advantage.

FIG. 15 is a perspective view illustrating appearance of a notebookcomputer in an open position according to a comparative example.

This notebook computer 910 includes a main unit 920 and a display unit930. The display unit 930 can be rotated around the hinge section 940 tobe freely opened and closed relative to the main unit 920.

The main unit 920 includes, on its top surface, a key board set 921, apointing device 922 that has been already described with reference toFIG. 7, a finger print sensor 926, and a cover member 927 which covers aportion corresponding to the hinge section 90 of the main unit 920.

The display unit 930 has a display screen 931 and a hinge cover section941 which is disposed in its lower end and included in a hinge section940 as a part of the display unit 930 casing. The hinge cover sectioncorresponds to the rod section 41 (see FIGS. 8 to 12) of the notebookcomputer 10 according to the present embodiment of the invention. Whilethe rod section 41 has a cylindrical shape, only the lower end of thehinge cover section 941 has an arc shape.

FIG. 16 is a perspective view illustrating a cover member of thenotebook computer according to the comparative example.

While the cover member 927 corresponds to the cover member 27 (see FIG.10) of the notebook computer according to the present embodiment of theinvention, only the upper end of the rising portion 972 has a reversed-Uarc shape because the cover member 927 is a resin-molded item, and thesize of a groove 972 a may be limited due to difficulties in a moldingprocess or an assembling process.

FIG. 17 is a perspective view illustrating a rear side of the notebookcomputer 910 in a closed position according to the comparative example.FIG. 18 is an enlarged view illustrating a notch portion 942 formed bymaking a cut in the hinge cover section 941.

As illustrated in FIG. 18, an arc-shaped portion of the hinge coversection 941 of the notebook computer 910 is horizontally protruded, andan arc-shaped portion of the cover member 927 (see FIGS. 15 to 17) isvertically protruded. In addition, a wall 946 defining a part of thenotch portion 942 of the display unit 930 is made flat in order to avoidinterference with the rising portion 972 of the cover member 927.

FIG. 19 is a top plan view illustrating a part of the hinge section ofthe notebook computer in the closed position according to thecomparative example, which corresponds to FIG. 14 according to thepresent embodiment of the present invention.

The notebook computer 910 according to the comparative examplestructurally has a slit 973 between the display unit 930 casing(specifically, the wall 946 illustrated in FIG. 18) and the risingportion 972. This fact also makes it difficult to provide harmoniousdesign for the hinge section 940.

(Connector Fixing Structure)

FIG. 20 is a perspective view illustrating a backside of the main unitof the notebook computer illustrated in FIG. 1 and FIG. 2 according tothe embodiment of the present invention, from which a bottom cover isremoved.

It can be seen that there are a number of components such as a circuitboard unit 50. Now, the circuit board unit 50 will be described more indetail.

FIG. 21 is a perspective view illustrating the circuit board unit 50being removed from the main unit 20 of FIG. 20. FIG. 22 is a perspectiveview illustrating a backside of the circuit board unit 50 of FIG. 21.

A variety of components are mounted on a circuit board 51 in the circuitboard unit 50. First of all, the structure of a heat sink unit 70 and anattachment structure for the power connector 25 of FIG. 1 will bedescribed.

FIG. 23 is a partially enlarged perspective view illustrating componentsinside a circle R3 of FIG. 22. FIG. 24 is a partially enlargedperspective view illustrating the same part as viewed from an angledifferent from that of FIG. 23.

Referring to FIGS. 23 and 24, there are illustrated a power connector 61mounted on the circuit board 51, a support member 62 which supports thepower connector 61 on the circuit board 51, and the heat sink unit 70mounted on the circuit board 51.

FIG. 25 is a partially enlarged perspective view illustrating componentsinside the circle R3 of FIG. 22 with the power connector 61 beingdisconnected by removing the support member.

The power connector 61 is not fixed to the circuit board 51 by solderingor the like. Rather, the power connector 61 is simply loaded on thecircuit board 51 and electrically connected to the circuit board 51 viacables 612.

In this case, a pair of openings 519 are formed on the circuit board 51by a drilling process. The openings 519 are spaced to receive the powerconnector 61. Each opening 519 extends along each side surface of thepower connector 61 and is right-angled at both ends. The reason why theopening 519 is right-angled at both ends is as follows. When each ofside plates 622 of the support member 62 is inserted into thecorresponding opening 519, surrounding plane surfaces of an end portionof the side plate 622 need to adjoin walls that define the opening 519.However, both ends of the opening 519 would be in the shape of an arc bya drilling process if no effort is made. Therefore, the opening 519 isright-angled at both ends.

FIG. 26 is a perspective view illustrating the supporting member 62.

The support member 62 includes: an upper plate 621 to adjoin the powerconnector 61; the two side plates 622 that are bent to extend from theupper plate 621 to be spread along a pair of side faces 611 (see FIG.25) of the power connector 61; and a fixed section 623 which extendsfrom the upper plate 621 to be fixed to the heat sink unit 70. The pairof side plates 622 are respectively inserted into the pair of openings519 (see FIG. 25) formed on the circuit board 51 to support the powerconnector 61. In addition, the fixed section 623 has an attachment hole623 a used to secure the fixed section 623 to the heat sink unit 20 viascrew. The heat sink unit 70 has an engagement section 721 having ascrew hole 721 a (see FIG. 25). The support member 62 is fixed to theheat sink unit 70 by a screw inserted into the screw hole 721 a of theheat sink unit 70 and the attachment hole 623 a of the fixed section623.

Further, the support member 62 includes a pair of engagement claws 624extending from the upper plate 621. The engagement claws 624 hold amating surface of the power connector 61 facing a counterpart connectorto prevent the power connector 61 from being moved in a dematingdirection toward the counterpart connector.

Further, an engagement protrusion 611 a is formed to vertically extendon each of the sides 611 of the power connector 61 (see FIG. 25). Theengagement protrusion 611 a adjoins a front end face 622 b of the sideplates 622 of the support member 62 so as to prevent the power connector61 from being moved in an insertion direction opposite to the dematingdirection.

FIG. 27 is a schematic diagram illustrating the counterpart connector 65to be mated with the power connector 61 on the circuit board.

The counterpart connector 65 is attached to a leading edge of a cableextended from an AC adaptor (not illustrated) for convertingcommercially available AC power into DC power appropriate to theoperation of the notebook computer. In most cases, if a user stays in apredetermined area, the notebook computer usually operates whilereceiving electrical power from the AC adaptor, and the counterpartconnector 65 of FIG. 27 is left inserted into the power connector 61 fora long time. In this case, the counterpart connector 65 may befrequently pushed in a direction indicated with an arrow A or pulled ina direction indicated with an arrow direction B as illustrated in FIG.27. If the counterpart connector 65 is impacted in an arrow direction A,the power connector 61 may be impacted in an insertion direction.Otherwise, the counterpart connector 65 is attracted in an arrowdirection B, the power connector 61 may experience a torsion force. Ifthe power connector 61 is directly soldered to the circuit board 51 in away similar to a conventional notebook computer, the bonded solder maybe exfoliated, and errors in the operation may occur. According to thepresent embodiment of the invention, since the power connector 61 issimply loaded on the circuit board 51 and connected to the circuit board51 via a cable 612, any impact or stress applied to the power connector61 is distributed to the support member 62 or the heat sink unit 70. Asa result, it is possible to avoid errors in operation caused by anyundesired impact or stress.

(Structure of Heat Sink Unit)

FIG. 28 is a perspective view illustrating the heat sink unit on thecircuit board by removing fixing screws used for fixing to the circuitboard and the support member. FIG. 29 is a perspective view illustratinga backside, which faces the circuit board, of the heat sink unit removedfrom the circuit board. FIG. 30 is an exploded perspective viewillustrating the heat sink unit by removing a cooling fan and separatinga cooling member from an attachment member. FIG. 31 is a perspectiveview illustrating the attachment member by removing a coil spring.

The heat sink unit 70 includes a cooling member 71, an attachment member72, a coil spring 73, and a cooling fan 74.

The cooling member 71 includes a metal plate 711 of FIG. 30 and a numberof cooling fins 712 erected from the metal plate 711.

Four attachment holes 711 a are formed at the corners of the metal plate711, and the cooling fins 712 are erected in a central area avoiding theattachment holes 711 a. FIG. 30 illustrates a bottom surface (also,referred to as a first surface) of the metal plate 711 which serves as asupport for the cooling fins 712 as well as adjoins heat-generatingelectronic components disposed on the bottom surface to absorb the heatand transmit it to the cooling fins 712. The cooling fins 712 areerected from the top surface (also, referred to as a second surface).

Mounted on the circuit board 51 of FIG. 29 are; a central processingunit (CPU) 511 that is one of the heat-generating electronic components;and two additional heat-generating components 512 and 513.

A metallic member 713 is soldered to the bottom surface of the metalplate 711 of the cooling member 71. Since the CPU 511 and theheat-generating electronic component 512 have different heights on thecircuit board 51, the height and location of the metallic member 713 isadjusted to allow the bottom surface of the metal plate 711 to adjointhe CPU 511 and allow the metallic member 713 to adjoin theheat-generating electronic component 512. The metallic member 713 formsa protrusion projecting from a reference face of the bottom surface ofthe metal plate 711.

The design of the metallic member 713 soldered to the bottom surface ofthe metal plate 711 to adjoin two heat-generating electronic componentsmakes the heat sink unit to be widely used for general purpose byadjusting the thickness of the metallic member 713 or adjusting thesoldering location even when the heat-generating electronic componentshave different heights or locations. That is, this structure allows theheat sink unit 70 to be compatible with a number of different types ofcircuit boards.

In addition, heat generated from another heat-generating electroniccomponent 513 is absorbed by the attachment member 72. The attachmentmember 72 includes a heat absorption section 722 adjoining theheat-generating electronic component 513, and the bottom surface of theheat absorption section 722 adjoins the heat-generating electroniccomponent 513. Formed on the opposite surface to the bottom surfaceadjoining the heat-generating electronic component 513 of the heatabsorption section 722 are a number of heat sink protrusions 722 a (seeFIG. 28) for emanating the heat absorbed from the heat-generatingelectronic component 513 to the air. Among the three heat-generatingelectronic components 511 to 513 and CPU 511 mounted on the circuitboard 51, the heat generation amount of the CPU 511 is the largest, andthe heat generation amount of the heat-generating electronic component512 is larger than that of the heat-generating electronic component 513.The heat sink unit 70 absorbs the heat based on the heat generationamounts of the heat generating electronic components 511 to 513.

The fan 74 of the heat sink unit 70 sends air to the cooling fins 712,and the air heated through the cooling fins 712 is externally dischargedfrom the main unit casing 20 through the air outlet 27 (see FIG. 8).

As illustrated in FIG. 29, the metal plate 711 of the cooling member 71is attached to the attachment member 72 by four screws 75. FIG. 30illustrates the cooling member 71 and the attachment member 72 arrangedside by side, by removing the fan 74 from the attachment member 72 andfurther removing the four screws 75 used to attach the cooling member71. The attachment member 72 has an opening 723 at which the coolingfins 712 of the cooling member 71 are disposed, and four fasteners 724protruding from the bottom and inserted into the attachment holes 711 aof the cooling member 71 around the opening 723. Each of the fourfasteners 724 has a screw hole 724 a (see FIG. 31) to attach the coolingmember 71 by fastening the screw 75 (see FIG. 29). Also, the attachmentmember 72 has an air inlet 725 to supply air to the fan 74 (see FIGS. 28and 29). Each of the four fasteners 724 is surrounded by a coil spring76 and inserted into the attachment hole 711 a of the cooling member 71.In this state, the four screws 75 are fastened as illustrated in FIG.29. As a result, when the heat sink unit 70 is mounted on the circuitboard 51, the cooling member 71 is pressed toward the circuit board 51by means of the four coil springs 76 interposed between the attachmentmember 72 and the metal plate 711 of the cooling member 71, so that theheat sink unit 70 can be sufficiently abutted against the CPU 511 or theheat-generating electronic component 512.

According to the present embodiment of the invention, using the heatsink unit 70 having such a simple structure, it is possible toefficiently cool heat-generating electronic components such as CPU 511on the circuit board 51.

While all the fasteners 724 are surrounded by the coil springs 76 in thepresent embodiment, the invention is not intended to be limited thereto.For example, the coil spring 76 may be selectively combined with anynumber of the fasteners 724 depending on the location of the heat sourcesuch as the CPU 511 relative to the cooling member 71. The bottomsurface of the metal plate 711 is rectangular, and the attachment holes711 a are formed at the four corners of the rectangle. For example, whena heat source is located near one side of the metal plate 711, the coilspring 76 may be provided for each of the screws 75 respectivelyinserted into two of the attachment holes 711 a near that side. By wayof another example, when a heat source is located near a corner of themetal plate 711, the coil spring 76 may be provided for each of thescrews 75 inserted into three of the attachment holes 711 a near thatcorner of the four attachment holes 711 a. Even in these structure, themetal plate 711 can be sufficiently abutted against the heat source byspring force while balance is retained. These structures may be helpfulto reduce cost, since the number of the coil springs 76 can be minimizedwith respect to the four screws 75.

In the present embodiment, the fasteners 724 having the same lengthsbased on the reference face of the attachment member 72 and the coilsprings 76 of the same type are used. However, the present invention isnot limited thereto. For example, depending on the location of a heatsource relative to the metal plate 711, the length of the fastener maybe shortened by partially raising a portion of the metal platecorresponding to the fastener 724. For example, when a heat source islocated near one side of the metal plate 711, the fasteners 24 near thatside may be shortened by partially raising a portion of the metal plate711 corresponding to two corners near that side. This structure mayallow the metal plate 711 to be a butted against the heat source bybalancing elasticity using the coil springs 76 of the same type.

Further, in the present embodiment, the screw holes 724 a are formed inthe fasteners 724 of the attaching member 72, and the screws 75 areinserted into the screw holes 724 a to install the cooling member 71.However, the structure of the heat sink unit 70 is not limited to thisstructure. For example, the circumference of the leading end of thefastener 724 of the attachment member 72 maybe threaded, and the coolingmember 71 may be installed using a nut or the like.

Furthermore, while the metallic member 713 is soldered to the referenceface of the bottom surface of the metal plate 711 in the presentembodiment, the present invention is not limited to this example. Forexample, when the heat sink unit 70 is applied to a circuit boardproduced based on a specific design, the bottom surface of the metalplate 711 may be raised from the reference face to form a protrusiondepending on the location of a heat-generating electronic component ofthe circuit board.

As described above, the electronic device described above in theembodiment provides improved selection freedom in its color or shape.

All examples and conditional language recited herein are intended forpedagogical purposes to aid the reader in understanding the inventionand the concepts contributed by the inventor to furthering the art, andare to be construed as being without limitation to such specificallyrecited examples and conditions, nor does the organization of suchexamples in the specification relate to a showing of the superiority andinferiority of the invention. Although the embodiment of the presentinvention has been described in detail, it should be understood that thevarious changes, substitutions, and alterations could be made heretowithout departing from the spirit and scope of the invention.

1. An electronic device comprising: a casing; a detachable cover havinga plate shape forming a part of a top surface of the casing; and anelectrostatic touch sensor disposed on an inner surface of the cover todetect a touch location of a finger on an outer surface of the cover. 2.The electronic device according to claim 1, further comprising a displayunit which has a display screen and is supported by a main unit to befreely opened and closed relative to the main unit, wherein the casingis a casing of a main unit having a keyboard disposed on a top surfaceof the main unit and an operational circuit, and the electrostatic touchsensor is a pointing device which controls movement of a cursor on thedisplay screen depending on movement of a user's finger touching theouter surface of the cover.
 3. The electronic device according to claim1, wherein the cover includes an engagement claw at an edge, and thecasing has an engagement hole in to which the engagement claw isengaged.